Vertical shale retort



July 14, 1953 H. J. HOLFORD ETAL VERTICAL SHALE RETORT 4 Sheets-Sheet 2Filed June 15, 1949 July 14, 1953 H. J. HOLFORD ET AL VERTICAL SHALERETORT 4 Sheets-Sheet 4 Filed June 15, 1949 r Jalm Che/Ills 2:22AM

Patented July 14, 1953 VERTICAL sHALE RETORT Hastings John Holford,Yatton, and Alexander John Challis, Bristol, England, assignors toHolford Processes Limited, London, England, a British company, andGeorge Adlam & Sons Limited, Bristol, England, a British'companyApplication June 15,1949, Serial No. 99,278 In Great Britain March 11,1949 3 Claims.

This invention relates to the distillation of carbonaceous material,such as shales, cannel coal, torbanite, other oil-bearing coals, peat orcellulosic material, and wood suitable for manufacturing charcoal, orother raw material such as nut shells adapted for the manufacture ofcharcoal.

A primary object of the present invention is to enable carbonaceousmaterial, or cellulosic material, or other raw materials suitable forcarbonisation to be subjected to destructive distillation in the samevertical retort in an improved manner, with or without the recovery ofby-prod ucts, such as liquid fuel, spirit, power and heating gases, tar,coke and other commercial byproducts. Another object is to provide animproved vertical retort for use in subjecting any of said materials tosuch-a distillation process.

According to a feature of the invention, there is provided a method ofdistilling carbonaceous or cellulosic materials, or other raw materialsadapted to be subjected to destructive distillation by carbonisation, bysubjecting the raw material to the destructive heating action of andcontact with a fluid heating medium as the material descends through avertical retort shaft surrounded by a vertically continuous jacketspace, characterised by externally heating the lower part of the retortshaft containing the zone of destructive distillation and also the upperpart of the retort shaft above that zone, by a fluid heating mediumflowing up the jacket space from the lower part to the upper partthereof, and thereby pre-heating the raw material fed into the retortprior to its reaching the zone of destructive distillation.

Preferably the raw material is fed in successive batches into thedestructive distillation zone with an appreciable time interval betweentwo successive batches, and the carbonaceous residue is preferablyremoved in batches from the lower end of the retort shaft with anappreciable time interval between two successive batches.

According to another feature of the invention provision is made forheating the retort shaft externally with gas, such as producer-gas, thatis admitted to the jacket space, and is obtained as a by-product fromthe retort.

Provision is also preferably made for supplying super-heated steam orboth separately or as a mixture into the externally heated retort shaft.

The invention also provides for use in carrying into practice theimproved method of distilling raw materials set forth above, a verticalretort comprising a retort shaft in combination with an external casingor jacket that is spaced away from the retort shaft and provides avertically continuous jacket space surrounding the retort shaft, meansarranged to pass a fluid heating medium up the jacket space and out ofthe top thereof, means arranged to admit a fluid heating medium to acharge of raw material in a lower destructivedistillation zone and in anupper preheating zone in the externally heated retort shaft, and feedmeans comprising an inlet valve arranged to feed the raw material in asuccession of batches into the retort shaft with a time interval betweenthe feed of each two successive batches.

The inlet valve and an outlet valve at the bottom of the retortpreferably both open downwardly and may be provided each withmanuallyoperated actuating means. Aternatively, mechanical means may beprovided for operating said valves in synchronism.

Conveniently the lower end of the retort shaft constituting thedistillation zone comprises two sections each of a frusto-conicalformation of different length joined together at their widest parts withthe shorter section directed downwards below the longer section.

Preferably, the bottom portion of the jacket surrounding thedistillation zone is of larger diameter than the upper portion andconstitutes a gas-heating chamber, into which tuyeres open for thesupply of heating gas to the entire jacket.

According to another feature of the invention, non-mechanical indicatingmeans is preferably mounted on the retort jacket for indicating a highlevel and a low level of the charge in the retort shaft as describedhereinafter.

Preferably the outlet at the bottom of the retort shaft surrounded bythe jacket opens downwards into a quenching device arranged to quenchcarboniferous solid residue discharged from the retort shaft.

This quenching device preferably comprises a water jacket with bafilemembers arranged within it, and quenching pipes associated with thebaflie members as described hereinafter.

Conveniently, a conveyor of the endless member type, such as a drag linkconveyor, is arranged below the retort shaft, preferably at the bottomof the quenching device for receiving the solid carbonized residue fromthe retort shaft and conveying it away. Means may be provided forconveying the quenched material and water to an oil separator.

and water continously to oil-separation ap- I paratus, and continuouslyremoving the separated oil and the spent material from which the oil hasbeen removed.

The invention further provides a distillation plant having one or morethan one bank of vertical retorts each as set forth above, wherein a'conveyor of the endless member type, which may be a quenching conveyor,is arranged to convey spent carboniferous material falling on to it fromthe outlets of all the retorts in a bank, and deliver it tooil-separation apparatus and to an elevated bunker for supplying rawmaterial to all the retorts in a bank will be described hereinafter.

The following is a description of a plant suitable for the recovery ofoilfrom shale, reference being made to the accompanying drawings inwhich:

Figure 1, divided into separate subfigures 1A and 1B, shows the generallay-out of the apparatus;

Figure 2 is a diagrammatic view showing the various steps in theprocess; and

Figure 3 is an enlarged vertical section and elevation of two of theretorts.

Referring to Figure l the shale from a store Ill or from a hopper wagonl l is delivered through a chute !2 to a conveyor [3. The conveyordelivers the shale to a bucket elevator Hi from which it passes througha chute to a roll crusher it, from the crusher it passes to anotherbucket conveyor !7 and thence to a screening device [8. The shale whichis to be distilled is passed from the screen to another bucket elevator19, while the dust from the screen is passed to a Redler conveyor 90.The shale to be distilled is delivered by the last-mentioned bucketelevator E9 to a conveyor indicated generally at which is of theextensible kind so that it may deliver into any of a number of hoppers2! arranged above a bank of retorts 22, theconstructionofwhich isdescribed later'. The spent shale after being quenched, in a quenchingdevice 23 at the bottom of each retort, falls onto a conveyor 243 of thewater trough type which conveyor extends away from the battery ofretorts and over the upper part of a settling tank 25 which removes thesludge and oil while the spent shale is delivered onto a conveyor 26leading to a dump. The settling tank contains an oil separator 21 of thetype described in British Patent No. 238,750 (complete specificationaccepted August 27, 1925), while the quenching water is delivered by apump 28 to a cooling tower not shown from whence it passes back again tothe quenching device 23.

The distillation gases from the retorts pass oil out from the topsthereof through a conduit 29 leading to condensers 30, ill and ascrubber 32 shown in Figure 2 and the gaseous fractions are stored in agas holder 33, whence, after being supplemented by gas from an auxiliarygas producer they pass back again to the retort, a part of the gasesbeing delivered into the interior of the retort through a conduit 35 anda part being delivered into jacket space through the conduit 36. Inaddition to the gas being passed into the interior of the retort thereis a supply through a conduit 38 of super-heated steam derived from asuper-heater 3?, Figure 2, which receives steam from a boiler 50. Inaddition the super-heater supplies steam to the auxiliary gas producer34 through the conduit 39.

The condensed oil from the condensers 30 and 3! passes through theconduits 4| and 42 to a dehydrator 43 and thence through conduit 44 toan oil refining plant, indicated generally at .45. The hot gases whichleave the jackets of the retorts pass through conduits 46 to a wasteheat recovery boiler M which leads hot water through conduit 48 to themain boiler 40.

Referring now to Figure 3, it will be seen that the retort comprises avertical mild steel tubular shaft 50 which is surrounded by brick work5! having a lining of fire bricks 52. The lining is spaced away from theretort shaft as to provide a jacket space 53 which iswidest at 5d nearthe bottom of the retort shaft, the bottom portion of the retort shaftis provided with a conical portion 55 widening as it extends downwardlyand which is connected with a conical portion 56 which narrows as itextends downwardly. This later conical portion is supported by a part51a of the fire brick lining.

The upper'portions 50 of the retort shafts are cylindrical in form andare secured together by bolts passing through flanges 58, being readilyportable whereby erection of the plant is facilitated. The retort shaftmay be formed from best quality boiler plate of 2832 tons tensilestrength made into tubular sections and having secured thereto anglesections whereby the parts of the retort shaft may be secured together.The other end of each retort shaft projects above the brick work at 59and is provided with outlet conduits 6i! which feed the aforesaidconduits 29 leading to the condensers. The upper extremities of theretort shafts terminate in funnel shaped members 6! which are fedthrough chutes 62 from the aforesaid hoppers 2|. As will be seen eachhopper 2i and chute 62 are mounted on a framework 63 disposed betweentwo retorts. A valve member 6 is associated with the bottom of thefunnel-shaped member 6! and another valve member 65 which is associatedwith the chute 62. A third conical valve member 65 is associated withthe outlet at the bottom of the conical section 56 of the retort. Thevalve members 64 and 56 are interlinked by mechanism not shown which isdriven through suitable gearing from a prime, mover so that periodicallya charge of shale is; introduced into each retort and spent shale is;released from the bottom of the retort. The con-.- ical valve member 66is slidably mounted on the. conduit 61 through which superheated steamorgas or both may be introduced into the retort. In the event of bothsteam and gas being employed separate concentric supply pipes may be"em-. ployed so that the gas and steam meet at the. nozzle 68 within theretort. The combustiblegases are introduced into the larger space 54 of'the jacket around the retort through nozzles ortuyeres 69 which are fedthrough the aforesaid: conduits 38. The distillation of the shale forthe most part, takes place in the lower portion of the retort providedby the conical portions 55 and 55, while the shale in passing downwardlythrough the upper portions of the retort is pre-. heated by the hotgases in the jacket space 53., The hot gases leave the upper part ofthis jacketspace through outlets lil which lead to the afore-. saidwaste heat conduits 46. A gas seal is provided between the'tubularretort and the jacket Wall by means of a skirt portion ll attached tothe retort and extending downwardly into a circumferential channel 12supported by a brickwork and lining.

When the conical valve 66 is closed and distillation is taking placethere may be a tendency for crude oil to collectat the junction betweenthe valve and the lower portion of the retort part 56. This oil may beled away through ports 13 in theretort part 56 which ports lead to achannel "M on the outside of the retort from which a delivery conduitextends. When the conical valve 6 6 is open the spent shale drops intothe quenching device 23 which comprises an encircling wall to which isattached a number of bafiie plates 15 inclined inwardly and downwardly.Spray pipes 16 are provided near the lower edges of the baffle plates sothat the spent shale falls through a showerof liquid and eventuallydrops on to the water channel conveyor 24. This conveyor comprises acast iron water-tight trough in which moves the upper run of an endlesschain provided with drag bars, which trough is provided at a waterdischarge point with a screen or grid permitting the water to drop intothe settling tanks hereinafter referred to. Air supply pipes 11 (notshown in Figure 3 but shown in Figure 2) are'provided for supplying airfor combustion of the gases both within the retort and within the jacketspace. The air may be supplied by inductionor by a fan. Similarly, aforce feed may be provided for the gas as by a booster indicated at 18in Figure 2.

Numbered indicating devices 79 for indicating the level of the shalewithin the retort may be provided at various levels, but in Figure 3only one is shown towards the top of the jacket space and comprises atubular casing 80 which extends through the jacket into an aperture inthe retort shaft and contains a photo-sensitive device such as aphoto-electric cell that it is connected to a control system comprisingan electric circuit containing a thermionic vacuum valve controlling arelay arranged to operate a visual or acoustic indicating device. Thearrangement is such that when the level of the shale in the retort shaftfalls below a low level indicator and rises above a high level indicatorthe respective indicating devices are actuated so that the outlet andthe inlet valves can be operated accordingly.

Thepre-heating zone or chamber constituted by the upper part of thejacket space is preferably made of solid highly refractory materialsurrounded by best quality brickwork, the whole being suitably stiffenedand supported by steelwork and tie-rods. The upper cylindrical portionof the brickwork surrounding the retort shaft preferably has mild steelangle bands 8| arranged encircling it at various levels. The brickworksetting carrying the lined jacket is preferably carried on brick columns82.

Eight thermo-coupled pyrometers (not shown) may be fitted to the retort,four in the gas-admission chamber at different levels, and one at otherappropriate points to give:

((1) Temperature of the superheated steam,

(b) Temperature of the gas entering both the preheating zone and thefiring chamber at the base of the retort shaft,

(0) Temperature of the gas and hydrocarbon vapour passing out of theretort shaft,

(d) Temperature of the gases leaving the preheating zone of the jacket,

All these pyrometers may be coupled to an instrument panel at apyrometer station. These pyrometers in conjunction with the high and lowlevel indicating or alarm devices provide for full control of theworking of the retort by the operator, and regulation of the conditionsof working is consequently very simple.

It will be appreciated that owning to the action of superheated steam,the interior of the retort shaft becomes quickly covered with a hard andimpenetrable scale, which obviates the necessity for a brick lining ofthe retort shaft, and consequently eliminates the heavy cost ofmaintenance and renewal of such a lining which is a feature of manyknown retorts used for carbonisation processes. The steel retort shaftmay be replaced by a tubular refractory shaft.

The described vertical retort may be used with or without by-productsrecovery plant as referred to above.

Preferably, however, a plant for distilling the carbonaceous orcellulosic material, particularly shale, by the method set forth above,comprises a plurality of the vertical retorts e. g. 20 thereof, arrangedin two rows forming two banks in one block. In such a block, the spentshale conveyor .24 below the quenching device at the bottom of one endretort may extend under all the other retorts in the bank to a quenchingand settling tank 25 or pit. This tank or pit may be sunk in, the groundand may be constructed of reinforced, concrete, and may comprise avertical partition wall 83 dividing it into two compartments where-- ofa larger compartment constitutes a sludgesettling tank situated belowthe said screen orgrid of the conveyor trough, and a smaller compartmentwhich is in open communication through the partition wall with thelarger compartment. The larger compartment may be provided with meansfor filtering the water, so that clean water can be pumped back to saidcooling tower and the quenching device. Oil in both of thesecompartments will float as a layer on the water in both thecompartments. Adjoining the pit and conveniently forming an end part ofthe same structure, is a third compartment 84 con-- stituting a pumproom accommodating an oil pump and a Water recirculating pump, abovewhich the trough conveyor extends to above the; end of a deliveryconveyor for spent shale leading to a dump.

The smaller compartment is preferably provided with a dehydrator 21 foruse in the gravitational separation of oil from the water. Thisdehydrator preferably comprises a vertical column provided with a seriesof bafiies and the liquid to -be separated is passed into the columnthrough a rota-table distributor which directs the entering liquidagainst a distributing surface. The rotatable distributor is preferablyin the form of a cap over the end of the inlet pipe, which cap is madewith inclined slots and vanes enabling the flow of the entering liquidto rotate it. The discharge of the oil is preferably effectedautomatically through an oil discharge valve at or near the top of thecolumn by means of lever control gear adjusted for varying gravities.The separated oil is allowed to flow out of the upper portion of thecolumn through a valve under the r control of a float adapted to sink inoil and float in water, while the separated water and impurities arewithdrawn from the bottom of the column. The valve-controlling float maybe mounted in a flat chamber external to the column, but communicatingwith it at the top and bottom. and, controlling the: oil .outlet valvethrough adjustable lever connections. The' oil pumpin the pump room iscontrolled by a float switch depending ,on'the level of the oil in" thepump room; The pit is of sufficient size to act as a cooling tank forreducing'the temperature of the water due to atmospheric conditions. The

"only'water lost will be by evaporation, and this can be replaced fromia supplypipe controlled bya float-controlled valve.

The banks :of retorts may be used. i'iLCOTII- bination with by-productrecovery apparatus,

which; is common to. them both, and. comprises one or morewater-cooledcondensers 33, for hydrocarbon volatiles and distillateliquor connectionby way of a liquor receiver, e. gra tarreceiver 35, ,with the volatileoutlet pipe 29 of each retort, andin addition, a gas-exhauster 83, agas-scrubber. 32, a water-circulating pump '3'! connected to thecondenser or condensers; In such a plant steam supply means may.comprise the gas-fired steam boiler, iii, and the-gas-fired steamsuperheater 3'lconnected therewith that are of sufficient capacity andare arranged to supply'superheated" steam to each retort in each banksimultaneously. I

The vby-product' recovery apparatus is connected by piping 29to thevolatile outlets of all the retorts of the banks. The aforesaid gas-.holder 33 may be connected by way of the gasscrubber 32and exhauster 86to the condensers 33, 3! for supplying gas to the steam boiler itand'superheater 37', and also for collecting gas in bulk-quantity forindustrial purposes. An ammonia recovery plant having a hydroextract'orassociated with it maybe connected each bank, and-when four such banksare pro vided it is possible to arrange a battery of from 8 up to '32retorts, with a by-product recovery plant common-tof them all. If morethan 32 retorts are required, then one or more additional banks may bearranged in parallel with the other banks, but theseadditionalbankswould require additional boiler, superheater' andcondensing plant.

We claim:

1. A distillation apparatus for oil-shale and materials having likeexpansion properties under heat, comprising a vertical retort shaft anupper part of which is of substantially constant. crosssectional areawhile the bottom of the retort shaft consists oftwo superimposedsections of frusto conical shape joined together at their widest parts,a jacket-wall surrounding the retort shaft so as to provide a heatingjacket space extending round the retort shaft over the greater part ofthe height thereofv from a position above the bottom'of the uppersection, the lower portion of the upper section and the whole of thelower section lying beneath the jacket space and being unheated, whichjacket space is of greater width around the upper portion of the upperof the two superimposed sections, means for introducing fluid heatingmedium both into the bottom of the retort shaft and into the jacketspace opposite the upper of the two superimposed sections, means forintroducing the materials to be distilled into the top of the retortshaft and means for releasing the spent material from the lower of thetwo-superimposed sections, which provides an outlet from the retortshaft.

2. A distillation apparatus for oil-bearing minerals, such as oil-shale,comprising a vertical retort shaft, which retort shaft is formed by acylindrical upper part and two superimposed sections of frusto-conicalshape joined to each other at their widest parts and secured, to thelower end of said cylindrical upper part, a jacket wall surrounding theretort shaft and spaced away therefrom so as to provide a heating jacketspace extending upwardly around the retort shaft from a position abovethe bottom of the upper section, the lower portion of the upper sectionand the whole of the lower section lying beneath the jacket space andbeing unheated, for the greater part of the height of said cylindricalupper part, said jacket space being of greater width around the upper ofsaid two superimposed sections, a nozzle in the bottom of the retortshaft for introducing fluid heating medium into the retort shaftgasburners in the jacket wall opposite the upper of said two superimposedsections and valve means for introducing the mineral into the top of theretort shaft and for releasing the spent mineral from the lower of saidtwo' superimposed sections, which lower section provides an outlet fromthe retort shaft.

3. An apparatus as claimed in claim 2 for the distillation ofoil-bearing minerals, such as oilshale, in which there are provided aquenching device below the retort shaft arr-anged to receive thedischarged spent mineral and a water and oil separator arranged toreceive quenched mineral and water from the quenching device.

HASTINGS JOHN nonnoen.

ALEXANDER JOHN CHALLIS.

References Cited in thefile of this patent UNITED sTAT-Es PATENTS NumberName Date 1,382,746 Schrader et a1. June 28, 1921 1,676,675 Trumble July10, 1928 1,822,541 Parker Sept. 8, 1931 1,922,321 Parker Aug. 15, 19332,165,143 Karrick July 4, 1939 FOREIGN PATENTS Number Country Date238,750 Great Britain Aug. 2'7, 1925 239,071 Great Britain Sept. 3, 1925381,831 Great Britain Oct. 13, 1932 403,623 Great Britain Dec. 18, 1933OTHER REFERENCES Bureau of Mines Information Circular 7348, May 1946,pages 50, 51 and Figure 10.

1. A DISTILLATION APPARATUS FOR OIL-SHALE AND MATERIALS HAVING LIKEEXPANSION PROPERTIES UNDER HEAT, COMPRISING A VERTICAL RETORT SHAFT ANUPPER PART OF WHICH IS OF SUBSTANTIALLY CONSTANT CROSS SECTIONAL AREAWHILE THE BOTTOM OF THE RETORT SHAFT CONSISTS OF TWO SUPERIMPOSEDSECTIONS OF FRUSTOCONICAL SHAPE JOINED TOGETHER AT THEIR WIDEST PARTS, AJACKET WALL SURROUNDING THE RETORT SHAFT SO AS TO PROVIDE A HEATINGJACKET SPACE EXTENDING ROUND THE RETORT SHAFT OVER THE GREATER PART OFTHE HEIGHT THEREOF FROM A POSITION ABOVE THE BOTTOM OF THE UPPERSECTION, THE LOWER PORTION OF THE UPPER SECTION AND THE WHOLE OF THELOWER SECTION LYING BENEATH THE JACKET SPACE AND BEING UNHEATED, WHICHJACKET SPACE IS OF GREATER WIDTH AROUND THE UPPER PORTION OF THE UPPEROF THE TWO SUPERIMPOSED SECTIONS, MEANS FOR INTRODUCING FLUID HEATINGMEDIUM BOTH INTO THE BOTTOM OF THE RETORT SHAFT AND INTO THE JACKETSPACE OPPOSITE THE UPPER OF THE TWO SUPERIMPOSED SECTIONS, MEANS FORINTRODUCING THE MATERIALS TO BE DISTILLED INTO THE TOP OF THE RETORTSHAFT AND MEANS FOR RELEASING THE SPENT MATERIAL FROM THE LOWER OF THETWO SUPERIMPOSED SECTIONS, WHICH PROVIDES AN OUTLET FROM THE RETORTSHAFT.